Correlation between Light Emissions from Amorphous-Si:H/SiO₂ and nc-Si/SiO₂ Multilayers

We investigate the properties of light emission from amorphous-Si:H/SiO₂ and nc-Si/SiO₂ multilayers (MLs). The size dependence of light emission is well exhibited when the a-Si:H sublayer thickness is thinner than 4nm and the interface states are well passivated by hydrogen. For the nc-Si/SiO₂ MLs, the oxygen modified interface states and nanocrystalline silicon play a predominant role in the properties of light emission. It is found that the light emission from nc-Si/SiO₂ is in agreement with the model of interface state combining with quantum confinement when the size of nc-Si is smaller than 4nm. The role of hydrogen and oxygen is discussed in detail.